1. Field of the Invention
A unitary wire welding lead assembly for use with a metal inert gas welding system.
2. Description of the Prior Art
Numerous metal inert gas (MIG) welding systems have been developed. MIG welding systems generally comprise four main components including an inert gas supply, a power supply, an electrode feed unit and a welding gun. The power supply converts high voltage alternating electrical current into low voltage direct current for the purpose of energizing the electrode wire and a low voltage direct current for operation of the electrode feed unit. The electrode feed unit includes a spool of malleable electrode wire which can be continuously fed through a hollow welding lead together with inert gas to the welding gun. The advancement of the electrode wire is controlled by a trigger switch on the welding gun connected to the power supply by control wiring through via the electrode feed unit.
While many refinements have been made in MIG welding systems, the present methods of connecting the electrode feed unit to the power supply and the inert gas supply continues to present several limitations. Electrode feed units are typically designed to be portable such that the units can easily be located adjacent to the structure to be welded. Conversely, the power supply and inert gas supply are typically less portable in terms of their weight, size and configuration. As a result, in most applications it is desirable to place the power supply and inert gas supply in a central location within the work area. The electrode feed unit is then moved through the work area as needed. Unfortunately, the combined bulk of the various wiring and gas conduits required often results in a cluttered work area and makes a cumbersome process of moving the electrode feed unit.
In practice, many users attempt to bundle or secure the various electrical wiring and inert gas conduit together with electrical tape. While this practice does lessen the space occupied by the leads, the practice must be repeated frequently as the tape fails under normal use. By combining the electrical wiring and inert gas conduit within a single elastomeric covering, the present invention eliminates the need for taping. Further, the concentric configuration of the components of the present invention, the wiring assembly is much more compact and flexible than taped bundles of wiring and inert gas conduits. As a result, the movement of electrode feed units is less cumbersome and can be moved throughout a larger portion of the work space without moving the power supply or inert gas supply.
Several MIG welding systems have been developed Which combine wiring and inert gas conduits in a unitary assembly. However, such assemblies have typically been applied to the connection between the welding gun and the electrode feed unit. Further, such systems do not include the improvements of the present invention including the flexible electrical in concentric combination with the inert gas conduit.
U.S. Pat. No. 3,992,565 describes a welding cable comprising a welding current conductor, switch wires and a gas conductor tube disposed with a single cable jacket. Passages containing the gas conductor tube and the switch wires are accessible through longitudinal openings in the jacket to facilitate insertion and removal of the switch wires and the gas conductor tube.
U.S. Pat. No. 3,703,622 shows a gas-shielded arc torch with a flexible shank between the head and the handle constructed to employ the inflowing gas to cool the electrode and head, to maintain high capacity in the torch while permitting its production in reduced scale.
U.S. Pat. No. 3,309,497 teaches a portable welding unit to continually feed welding wire comprising an enclosure providing a support structure and being adapted for suspending from a welder's body; a container for welding wire to be supplied to the device, and flexible means connected at one end with the support for guidingly carrying welding wire the welding device, whereby the welder is free to move from one welding position to another without being limited by the length of said flexible means.
DE 30 10 451 A 1 describes a cable supplying electricity during, e.g. MIG arc welding. The novelty is that the conductor wires are not arranged concentrically as in the main patent, but form a circular row providing optimum current distribution and better removal of heat from the cable. The new cable is also easier to connect to standard, commercially-available couplings. An elastic tube is used to carry gas forms the core of the cable; and on the core are two semicircular rows of conductor wires separated from each other by insulating cords, which may contain a conductor employed to carry a subsidiary electric current used for control circuits.
Additional examples of the prior art are shown in U.S. 3,433,883 and JP 6-315,770.